drm/connector: print max_requested_bpc in state debugfs

This is useful to understand the bpc defaults and
support of a driver.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Sebastian Wick <sebastian.wick@redhat.com>
Cc: Vitaly.Prosyak@amd.com
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joshua Ashton <joshua@froggi.es>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Reviewed-By: Joshua Ashton <joshua@froggi.es>
Link: https://patchwork.freedesktop.org/patch/msgid/20230113162428.33874-3-harry.wentland@amd.com
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org